1. Field of the Invention
The subject invention relates to a communication system having at least two communication formats. More particularly, it relates to a telephone system adapted to be switchable between a full service two-way communication format and a partial two-way communication format having an acknowledgement response.
2. Background of the Invention
Conventionally wired telephone systems, as well as cellular telephones are well known in the art. Similarly, mobile pagers are also well known in the art. While each art has advanced to a sophisticated level, there are still a number of shortcomings associated with each.
Cellular telephones have gained wide-spread acceptance over the recent years. The trend in growth of the cellular telephones has continued to be positive, especially as the technology has evolved to enable reductions in the size and weight of portable cellular telephones. However, two distinct disadvantages are still associated with portable cellular telephones.
First, even though the number of regional areas covered by cellular communications system antennas has greatly increased over the recent years, the cell coverage available to a portable cellular telephone user is still relatively limited compared to conventionally wired telephone systems. For example, frequently when the cellular telephone user travels outside a major urban or suburban region covered by cellular communications system antennas, the user will fall outside of cellular communication coverage rendering the portable cellular telephone inoperative until once again the user travels within a cellular covered region. Further, the cost of operation associated with portable cellular telephones is still somewhat expensive relative to conventionally wired telephone systems.
In contrast to the portable cellular telephone, a paging system is a one-way radio communication system. For example, an individual wishing to contact someone with a pager usually calls a central telephone number to access the central paging control. Once accessed, the caller can either leave a voice message for the paged individual or can key in a desired telephone number or text message to be displayed on the pager's display.
The pager solves some of the aforementioned problems associated with the portable cellular telephone. A mobile paging unit has a much greater region of operability in contrast to the limited operable range of the portable cellular telephone due to the high power of the paging base station transmitter. Further, operation of a pager unit may be employed for a much lower cost relative to the aforementioned high cost associated with the portable cellular telephone. A pager allows a user to receive the number of the calling party, thereby enabling the pager user to screen incoming calls so as to determine which telephone number to call back, thus eliminating the charges for unwanted calls which are commonly associated with portable cellular telephones.
However, a distinct shortcoming associated with paging units are their inability to establish two-way communication. Therefore, while the pager solves some of the limitations associated with portable cellular telephones and vice versa, the user has the burden of carrying and maintaining both devices so as to gain the advantages of both devices and mitigate the disadvantages associated with each.
An obvious solution to obviate the problem of carrying a portable cellular telephone along with a pager unit is to integrate a cellular telephone with a pager unit into one communication component. Examples of this can be found in U.S. Pat. Nos. 3,247,700 to Wohl et al., 5,175,758 to Levanto et al., 5,153,903 to Eastmond et al. and 5,117,449 to Metroka et al. However, a disadvantage exists with an integrated cellular telephone and pager, in that such a device is still only capable of establishing full two-way service communication, via the cellular telephone components, or no return service, i.e., the one-way service provided by the pager unit. For example, when such an integrated cellular telephone and pager travels outside a region covered by a cellular communications system antenna but is still within a region covered by a pager system antenna, the integrated device is inoperative to respond to a received message, via the pager unit. Further, when such an integrated device is within a region covered by a cellular communications system antenna, the integrated unit only provides the user with the options of either responding to a received paged or telephone message through the expensive method of establishing full two-way service communication through the portable cellular telephone or not responding at all. Thus, if the user desires to respond to a received paged message, the user must implement the costly method of establishing two-way communication via the cellular telephone.